If you previously unlocked your iPhone 3G or 3GS, chances are you are on the 6.15.00 baseband. This baseband is also known as the iPad baseband and many users have reported inconsistent GPS signal. Follow the step-by-step video below to get your baseband downgraded to a more stable, unlockable, version. In this video, we will be downgrading our 6.15.00 baseband to the more desired 5.13.04 baseband. As always, the download links are below for your convenience.

my iphone 3g has a usb cable and itunes logo on front cant get past it i have tried downgrading using this way tried re jailbreaking couldnt figure anything out i cant get to the homescreen so i am unable to do anything settings wise from inside the phone its a customers phone that they went home and tried to upgrade not sure what ipsw it is on i think it is the 4.2.1

I made the steps and my baseband was changed well, after that I installed the ultrasn0w but no service. I want to use the phone with t-mobile. Maybe my mistace is that I did it the earlier IPSW on what was installed the ultrasnow and ultrasn0w fix??Should I intsall a new IPSW and after install ultrasnow??

help pls!
after following the steps while my iphone 3gs was on the last step of the process it says on my iphone screen ( transferring control to jailbreak dyld: code signature for shared cache failed with errno=7) what should i do to fix this? your help will be much appreciated.

i got the same result as Queen… desperately trying to fix 3gs iphone cant get pass connect to itunes i thought it was gonna work redsn0w says done… than on my device.. tranffering control to jailbreak… dyld: code signature for shared cache failed with errno=7

JUST TO BE MORE SPECIFIC THE SCREEN SHOWED THE PINEAPPLE N ALL THE CODES THEN GOT STUCK tranfering control to jailbreak… dyld: code signature for shared cache failed with errno=7 WHAT DOES IT MEAN HOW CAN I FIX THIS PLZ HELP

Hello Ian, I came across your video “How to: Downgrade iPhone 6.15.00 (iPad Baseband) on iPhone 3G/3GS” because I keep having the “No Service…Searching…” issue. I must say your videos are selfless and I commend your contributions.
I followed your guide in the video but on getting to the Jailbreak part on RedSn0w where I have to put my iphone in DFU mode, I encountered an error “Ipad baseband failed” and could not proceed.
My iphone 3GS is on version 4.1 firmware 6.15.00.
How do I successfully downgrade my firmware? Am I applying the right solution? Am I doing it right?
Thank you in anticipation of your kind assistance.

I am getting the same problem, of the missing keys.plist data for this build. If I try to downgrade the BB to 5.13.04 I get the errno=7 error coming up. Even when the phone gets through this it is still on 6.0.1 and is showing no sim with no change in the BB. Help is desperately needed as I have been trying to sort this for a couple of months now and am getting desperate.

I have an iphone 3gs 16 GB which is on ios 4.1 and baseband 6.15.00. I want to change to baseband 5.13.04. I saw the video on youtube but that was for ios 5.1. will it work on my phone too or lemme know wat to do…

hey ian….. 🙂
ive updated my iphone 3gs to iOS 6.0.1, stuck on the activation screen, then did the procedure on your video tutorial (here: http://www.youtube.com/watch?v=xBWnbkGXHDk).. it worked though but im having this “no service” thing..can i do this tutorial of yours on downgrading my 6.15.00 BB to 5.13.04?? i mean, would this procedure be safe? i dont want to get my iphone bricked… pls, do reply. :s

Today i bought my desired iphone 3gs so iam a new user and i dont know mouch about them. i conected it to itunes and it showed me that i can upgrade it. then it stuck in recovery mode with error1015. I tried almost everything. your tutorial how to fix i tried too. the program turned immediately off as i turned my iphone into DFU. please , if u can contact me on my email robladziansky@gmail.com , and help me to fix this problem it will be great. I tried to change my ios too. when i tried it to install it to iphone via itunes it said to me that it isnt compactible.

Alright Ian, I need help. I used the above video 3 times on 3 different 3G’s that all had 4.2.1 & 6.15.00 and 2 of the phones downgraded just fine. the third one goes through the motions but does NOT downgrade BB. Why is this﻿ not working???

Hi, Guys, I´m facing a similar problem. I have an iPhone 3GS IOS 4.1, old bootrom, baseband 06.15.00. I did al the recipy from iClarified, using both redsn0w 0.9.14b1 and 0.9.15b3 with two different computers.
After the redsn0w does what it is supposed to do, a series of commands can be seen scroling in iPhone’s screen until the phrase “Transferring control to Jailbrake” gets stuck for 5-10 minutes and then other commands start scrolling.
The phone reboots without appearing the Pineaple and nothing seems to have happened.
Can anyone help me?

I followed same procedure to downgrade. But When I try and downgrade the software, I run into an error on the phone – “Transferring control to jailbreak…dyld: code signature for shared cache failed with errno=7”.
What to do?